Corrugated tube manufacture



1948. w. G. HARDING 2,446,281

CORRUGATED TUBE MANUFACTURE Filed May 11,1944 2 Sheets-Sheet 1 INVENTOR.

A T TOBNEY Aug. 3, 1948. w HARDING 2,446,281

CORRUGATED TUBE MANUFACTURE Filed May'll, 1944 2 Sheets-Sheet 2 R Q NEM;-LA67 o A T TORNEY Patented Aug. 3, 1948 gUNlTED armrest opticsillnited "States Rubber.

N; Y., a corporation of Newders'ey 1* finalisati -Ma 134:4.asrtiatNoafisallz dma-ims. 1 I This invention relates ,to an improvedmethod and; apparatus for makin internally reinforced 1-1 flexiblecorrugated tubes, having. annular .corrug-ations, reinforced with. ringspositioned ..Within :the .interiorvalleys of the corrugations.

Corrugated tubes are made from. deformable plastic treated textilefabric tubular. casings which. are subsequently corrugated. f1 .Inaccordance-awith my. invention reinforcing rings are :(RLECGCI; in theinterior of such deformable tubulaigcasings in spaced vrelation .toeachothenwith :the peripheries .otthe, rings in contactwith the casings.The casings arethen collapsed longitunallyto produce a-corrugatedtubehavingf the .i npreyed. combined qualities of flexibility and retsistancelto external pressure. Theuseof thevapparatus and. method hasthe furtheradvantage z p-f increasing therate-of production of tubesover ,methods'heretofore employed.

.. This inyentlonis iurtherdescribedin. reference tcthea ompa na d awinnwh ch:

, li'ig. 1;. is; a I longitudinal ,cross -section-of acorqqzugated-itube -made;by. my improvedmethodt and -,..anuaraius;

Eig, 2 4s alongitudinal cross-sectional, yiew of .an,e1ement oi my.invention comprisinsaninflatablewmandrel. used to insert frein forcingrings within the tube to be corrugated; 3 is alongitudinal cross-sectionof the mandrel. shownin Fig. 2 after it hasbeen inflated to seourethe-reinforcingrings thereon,.and.of a related portion of the apparatus,illustrating.v the u method of assembly of the reinforcing rinwithmettle-tub "Fig, his alongitudinal cross-sectional .view ;of

..,Ithe ,.partsof the apparatusshown in Fig, 3,- but 'apparatus'is showniii-Fig. 1 of the drawings,jand

iiroomprlses acorrugated'tube l having annular corrugations H in whichare located-supporting -*-'or-reinforcing* members in the form of' ringsl2. *TBhe i-ngs: l2 are made of arelativelyjrig-idmategr-ial and-theirannuli arepreferablyin one solid c1251s s) piece; that is. they areundivided. The .outer pegripheriesf-l 3 iofitheringsengage and supportthe interior surface M of the-corrugations l l at their greatestdiameter. The inner peripheries it of if-the rings. ',l2..project withinthe interior valleys .I6,,fof the corrugations H. 'Th corrugated tube.lllandits walls are' fiexible and .therings increase t the resistance.of-the walls. against being radially r-collaps'ed by.the. exteriorapplication of pressure in-the,radialdirectionand without substantiallydecreasing the flexibility of the tube in respect to axialbending-movements and elongation. The

. tube is preferablymade of atextile fabric impregnatedor coated with aflexiblematerial to render lfi'fit impervious to gases and liquids. Suchimpreg- .1',1 a,t r 1g .orcoating materials maybe rubber, or ,pr'ribber;compositions, or synthetic plastics, which I can be' treated after thetube has been shaped tO..Qau sej"the'shapetobe retained. The tube may.20 also be; made from rubber or rubbercompositions 101'. othersynthetic materials which will provide the necessary flexibility andstrength after being set as byyulcanization, or. other treatment.

f'lhemethod and apparatus .for manufacturing gsf thetube'isdisclosed inFigs. Zto 8, inclusive. The

' tube "I 0, in .,its ini ti al stage .before being corrugated; has a'snooth outer surface. and. it is adapted to be' deformed 'into the desiredshape by ",istr'etlching'it raditllygand collapsing it longitudi--na'lly. In the practice of the method as shown -'in='-Fig". Sgt'ube |7,'tC be corrugated from its initial -fst-age isenclosedwithin aretaining. tube l8 which (latter may be; madeaof canvas and providedwith a reinforcing band l8. One end of the tube I1 =is-clampedbetween anair nozzle 19 and the adjacenttend ofithe tube l8. 7

Referring .to Fig; 2, the'rings 12 are inserted -in the tube J'L bysecuring them on an inflatable mandrel -20. :The'external'diameter. ofthe mam 40"dfe1iS' ln a;11I' thanthe internal diameter of the "ringsiiZand it is. provided with axially spaced annular grooves 2 iv which areadapted to receive the internal periphery ofitherings l2. After theringsare placedupon the mandrel, the latter is expanded radially .by.admitting fluid under. pressure to; its internal cavity 22 from a supplypipe f 2 3 jand.thepressure expands'the mandrel to the position ,asshown in Fig; 3 so, as to securel hold 'gfthe rings jl2 inplace;but'be'fore the mandrel is Q in sertedin the tube l. The fluid pressureis conftIfQHed 'byaValve 24 which is, adapt-ed tofadmit .the pressure'fromfl the pipe. .23. to'the pipe in) "'which extends. into'th mandrel.253. Thefluid is charged; into fthe mandrel through th open- .esflfiflntheipipeiz'i.; Preferably the inner; end

21 of the pipe 25 is anchored in the end 28 of the mandrel 2B in orderto give greater rigidity thereto and to prevent it from extendinglongitudinally when inflated. The end of the pipe 25 adjacent to thevalve 24 extends through and is sealed in a bore 29 in a plug 30 in theend of the mandrel 20. The plug 30 is held in sealed relation with themandrel 20 by means of an external clamping ring 3|.

The valve 24 is so constructed that it can admit fluid pressure from thepipe 23 to the pipe 25 in one of its positions, and so that it can cutoff the fluid pressure from the pipe 23 and discharge the fluid pressurefrom the pipe 25 to the atmosphere through the discharge outlet 32. Asshown in Fig. 2, the valve 24 is in its position to cut ofi the fluidpressure from the pipe 23 and discharge it from the pipe 25. Across-section of the valve in this position is shown in Fig. 6 of thedrawings. In order to inflate the mandrel 2c and expand it radially tosecure the rings 12 thereon, the valve 24 is turned to its admittingposition, as shown in Fig. 5.

The rings l2 having been secured on th mandrel 20, air under pressure isnow admitted through the nozzle [9 into the interior of the tube H, andthe mandrel 20 with the rings l2 thereon is inserted in the end of thetube H. The tube [1 is initially smaller than the rings, but the builtup air pressure within the tube I! causes it to expand radially topermit the rings l2 to be inserted and positioned therein as shown inFig. 4. During the ring inserting operation the tube I! may be expandedagainst the retaining tube [8 and the latter will prevent the tube I!from being strained. The air escapes from the free end of the tube ll,between it and the outer diameter of the rings l2, and thereby providesa cushion or film of air between the rings and the interior Walls of thetube [1. This cushion of air permits the mandrel 210 to be easilyinserted within the tube H.

As shown in Fig. 4, a cut-off valve 33 is inserted in the air supplypipe 34 leading to the nozzle I9 to control the supply of air to theoutlet 35 of the nozzle. During the inserting movement of the mandrel,the valve 33 is in its on position and admits the air to the tube ll,but the valve, as shown in Fig. 4, has been turned'to its oif positionin order to cut off. the air supply and permit the tube I! to contractradially and tightly engage the outer diameters of the rings 12. Thisbeing done, the mandrel valve 24- is turned to'its exhaust position, asshown in Fig. 6 so as to permit the mandrel 20 to contract radially tothe position shown in Fig. 2. In such position the rings I2 are releasedfrom the mandrel 20, and as they are now tightl engaged by the innerwalls of the tube I! the mandrel may be disengaged from the rings l2 andremoved from the interior of the tube IT. The mandrel is removed and therings l2 are retained in the tube H, as illustrated in Fig. 7.

The nozzle I9 is then removed from the endof the tube I! to release it,and the tube with the rings l2 therein is then removed from theretaining tube IS. The tube I! will then present the shape as shown inFig. '7. The tube I! with the rings gripped thereby is then placed uponthe mandrel 36 (Fig. 8). Rings 37 are slipped over 4 corrugations H withthe rings l2 secured in the interior valleys I6 of the corrugations.While the tube I1 is retained in that position, it is treated so thatthe corrugations will be retained in the tube i'l after it has beenremoved from the mandrel 36 and released from the endwise pressure. Suchtreatment may involve retaining the tube in the position shown in Fig. 8for sufiicient length of time so that it will be permanently set, or ifthe tube contains a thermosetting material it may be subjected to heatto produce the permanent set, or if the tube contains a plasticplasticiser it may be set by evaporating the plasticiser, as is wellknown in the art. After the tube IT has been so treated, the rings 31and the mandrel 36 are removed therefrom. The tube I"! will then beconverted into the tube [0 as shown in Fig. 1 of the drawings, or it mayretain its shape as shown in Fig. 8, depending upon how tightly thecorrugations have been pushed together and how permanently the tube hasbeen set.

While I have described this invention mor or less in detail. it may beunderstood that changes may be made therein without departing from thespirit of the invention and the scope of the appended claims.

Having thus described my invention, what I claim and desire to protectby Letters Patent is:

1. Method of making an internally reinforced corrugated tube comprisingthe steps of inserting rings in a deformable tubein spaced relation toone another and with their outside diameters in tight contact with theinside surface of said tube, and forcing said ring towards each otheralong the axis of said tube so as to collapse the Walls of said tubeinwardly between said rings and permanently secure said rings therein.

2. The method of making an internally reinforced corrugated tubecomprislng the steps of expanding the circumference of a deformabletube, inserting rings in the expanded tube in spaced relation to oneanother and with their outtubes inwardly between said rings.

the smooth ends 38 of the tube i! in close engagement therewith. Therings 31 are then cumferentially,

said tube.

ference of a deformable tube under fluidpresv sure, inserting rings inthe expanded tube in spaced relation to one another and with theiroutside diameters in contact with the inner surface of said tube,releasing said pressure, and forcing said rings towardseach other alongthe axis of said tube 'so as to collapse the wallsof said 4. The methodof making an internally reinforced corrugated tube comprising the stepsof stretching a plastic vulcanizable rubber tube cirinserting ringsWithin said stretched tube in spaced relation to one another and withtheir outside circumferences in tight contact with the inner surface ofsaid tube, forcing said rings towards each other along the axis of saidtube so as to collapse the walls of said tubes inwardly between saidrings, and permanently retaining the rings therein by vulcanizing saidtubes so as to retain the corrugatedcondition of 5. The method of makinga corrugated tube 1 comprising the steps of inflating a plastic, vull'canizable rubber tube within and against the mner walls of a fabrictube under fluid pressure and stretching said rubber tubecircumferentially, inserting rings within said stretched tube in spacedaxial relation to one another and with their outside diameters in tightcontact with the inner surface of said tube, releasing said pressure,forcing said rings towards each other along the axis of said tube so asto collapse the walls of said tubes inwardly between said rings, andvulcanizing said tubes so as to retain the corrugated condition of saidtube.

6. In an apparatus for making corrugated tubes, comprising means fordiametrically expanding an elastic tube and subsequently permitting saidtube to contract, a mandre1 adapted to insert rigid rings in saidexpanded tube, said mandrel comprising means for retaining said rings inspaced relation thereon, and means cooperating with said' mandrel forreleasing said rings in contact with said contracted tube.

7. A mandrel for inserting rings in axially spaced relation within atube, said mandre1 comprising an inflatable elastic cylindrical mandrel,said mandrel having means thereon for locating said rings in axiallyspaced relation while said WATSON G. HARDING.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 24,222 Burney May 31, 18592,039,781 Debenedetti May 5, 1936 2,347,086 Curtiss et al Apr. 18, 19442,347,101 Harding Apr. 18, 1944

